The wrist band that came with my Garmin Forerunner 205 was knocking against my wrist bone and bruising it. Ouch! My husband found one for me at Amazon.com for about $20, including shipping.
Because the new band is Velcro, I can adjust it to fit my wrist. I don't have to remove the strap to load my workout onto my computer, but it's quick to remove (now that I've done it a few times) and I do have to take it off to wash it.
When I noticed the wrist bruise I did some experimenting. To keep the heavy watch face from hitting my wrist bone, I twisted my watch around so that it faced me. Since then, I always wear my watch backwards. It's easier for me to look at the inside of my wrist than the outside while I'm running.
Pic: That's my Garmin Forerunner 205 with the Velcro wrist band and my dog waiting for her doggy treat. Good dog!